Hi,
what can i do to stop this?

Sometimes Backup and Statistics run at the same time and WORSE.. at mid of the day, when server is highly overloaded....

Is there any way to schedule Backup or/and Statistics to run ONLY at 03:00-09:00 AM ?

My CPU is getting only 30% free (average) when this happens.

It is set to run in the "evening" however I imagine your problem is that your timezone is not set. If you set the timezone to your local area it will probably solve your problem.